Nope, you're not missing anything. I had the exact same reaction when I wanted to write a script.

Basically, you just have to write the script in the text editor of your choice, then try it out in Poser. IDE? What's that?

FWIW, I use IDLE, which comes free with the standalone Python production release. Nothing special -- keeps nice python indentation, automatically highlights reserved words, that sort of thing. When I'm organized, I try to stub out poser related stuff, so I can use IDLE to try out Tkinter routines outside of PP/P5. But you always have to do final development within Poser, because sometimes even the Tkinter widgets look different when created by the PoserPython interpreter. (Nothing significant, just the alignmnent is just a little off sometimes).